The present invention relates to packaging machines in which a series of folding boxes fed one after another in a predetermined direction with a substantially constant center to center distance are processed in various stations and, more particularly, to a box flap folding station for such a machine which is adjustable for processing different size boxes.
Principally, such a machine comprises an endless conveyor, such as a chain or a band running in the horizontal plane and provided with equally spaced carriers for folding boxes of cardboard or similar material. From a plane condition in a storage area the folding boxes are fed to the conveyor and simultaneously erected into a substantially case-shaped configuration with top and bottom endwall flaps extending from the body portion of the folding box. In a conventional machine of this type the erected folding boxes are conveyed to the following stations: a transverse-wall and longwall flap unfolding station, a sealing strip application and sealing station, a sealing strip cross-cutting station and a flap folding and sealing station. These stations are located along a rectilinearly extending portion of the conveyor and operate upon the bottom ends of the folding boxes. After the bottom sealing has been accomplished, at the end of the rectilinear portion the folding boxes are filled in a filling station, preferably situated along a curved portion of the conveyor after which the folding boxes are conveyed along a second rectilinear portion in a direction opposite to that of the first rectilinear portion. With the exception of the transverse-wall and longwall flap unfolding station, the second rectilinear portion is provided with stations identical with those of said first portion, however with the difference that the latter operate upon the top ends of the folding boxes. At the end of the second rectilinear portion there is a discharge station for the filled and sealed folding boxes.
Basically, this machine is reliable and practical. However, it would be desirable to provide a flap folding station which is operable within a maximally large size range. With the known machine in such a case unfavorable stresses in the flaps are obtained at certain sizes and difficulties arise when the distance is small between adjacent flaps of successive folding boxes.
It is therefore an object of this invention to provide flap folders having optimal paths of travel with respect to stress loading of the flaps.
It is a further object of this invention to simply adjust the paths of travel and to simultaneously ensure that the paths will be optimal as regards to the intended inwards folding of the flaps for various folding box sizes.